Propylene Glycol Potentiates the Inhibitory Action of CTZ Paste on Antibiotic-Resistant <i>Enterococcus faecalis</i> Isolated from the Root Canal: An In Vitro Study

Abstract

This study aimed to evaluate if the change of vehicle for CTZ (Chloramphenicol, Tetracycline, zinc oxide, and Eugenol) paste improves the inhibition of Enterococcus faecalis in vitro. The vehicles evaluated alone and mixed with CTZ were Eugenol, propylene glycol (PG), super-oxidized solution (SOS), grapefruit-seed extract (GSE), and 0.9% saline solution as a negative control. A clinical isolate of E. faecalis was morphologically and biochemically characterized, and its antimicrobial susceptibility was tested using 20 antimicrobial agents. Once characterized, the clinical isolate was cultivated to perform the Kirby–Bauer disc diffusion method with paper discs embedded with the different vehicles mixed or used alone, and incubated at 37 °C for 24 h. Data were analyzed using one-way ANOVA, and the means were compared using Tukey test with a significance level of p E. faecalis in vitro; therefore, we consider that this can be an important factor to achieve success in the use of this technique.

Keywords

• CTZ paste
• grapefruit-seed extract
• propylene glycol
• antibiotic resistance
• <i>E. faecalis</i>